According to those environmental planners, shading from strategically placed street trees can lower surrounding temperatures by up to 6 degrees – or up to 20 degrees over roads. Green roofs and walls can naturally cool buildings, substantially lowering demand for air-conditioning.

By contrast, hard surfaces – including concrete, asphalt and stone – increase urban temperature by absorbing heat and radiating it back into the air.
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Why plantscrapers are springing up across the globe
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Why plantscrapers are springing up across the globe

But though scientists have much evidence that trees and other greenery improve our mood and health, they know less about the actual mechanisms by which this occurs. Japanese research, however, suggests that when we walk through bushland we breathe in three substances: beneficial bacteria, plant-derived essential oils and negatively-charged ions.

We live our lives surrounded by beneficial bacteria, breathing them in and sharing our bodies with them. Gut-dwelling bacteria break down the food we can’t digest and produce substances that benefit us physically and mentally.